/*
 *    Copyright 2009-2012 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.apache.ibatis.builder;

import org.apache.ibatis.mapping.ParameterMode;
import org.apache.ibatis.mapping.ResultSetType;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeAliasRegistry;
import org.apache.ibatis.type.TypeHandler;
import org.apache.ibatis.type.TypeHandlerRegistry;

import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

/**
 * @author Clinton Begin
 */
public abstract class BaseBuilder {
    protected final Configuration configuration;
    protected final TypeAliasRegistry typeAliasRegistry;
    protected final TypeHandlerRegistry typeHandlerRegistry;

    public BaseBuilder(
            Configuration configuration) {
        this.configuration = configuration;
        this.typeAliasRegistry = this.configuration
                .getTypeAliasRegistry();
        this.typeHandlerRegistry = this.configuration
                .getTypeHandlerRegistry();
    }

    public Configuration getConfiguration() {
        return configuration;
    }

    protected Boolean booleanValueOf(
            String value,
            Boolean defaultValue) {
        return value == null ? defaultValue
                : Boolean
                .valueOf(value);
    }

    protected Integer integerValueOf(
            String value,
            Integer defaultValue) {
        return value == null ? defaultValue
                : Integer
                .valueOf(value);
    }

    protected Set<String> stringSetValueOf(
            String value,
            String defaultValue) {
        value = (value == null ? defaultValue
                : value);
        return new HashSet<String>(
                Arrays.asList(value
                        .split(",")));
    }

    protected JdbcType resolveJdbcType(
            String alias) {
        if (alias == null)
            return null;
        try {
            return JdbcType
                    .valueOf(alias);
        } catch (IllegalArgumentException e) {
            throw new BuilderException(
                    "Error resolving JdbcType. Cause: "
                            + e, e);
        }
    }

    protected ResultSetType resolveResultSetType(
            String alias) {
        if (alias == null)
            return null;
        try {
            return ResultSetType
                    .valueOf(alias);
        } catch (IllegalArgumentException e) {
            throw new BuilderException(
                    "Error resolving ResultSetType. Cause: "
                            + e, e);
        }
    }

    protected ParameterMode resolveParameterMode(
            String alias) {
        if (alias == null)
            return null;
        try {
            return ParameterMode
                    .valueOf(alias);
        } catch (IllegalArgumentException e) {
            throw new BuilderException(
                    "Error resolving ParameterMode. Cause: "
                            + e, e);
        }
    }

    protected Object createInstance(
            String alias) {
        Class<?> clazz = resolveClass(alias);
        if (clazz == null)
            return null;
        try {
            return resolveClass(alias)
                    .newInstance();
        } catch (Exception e) {
            throw new BuilderException(
                    "Error creating instance. Cause: "
                            + e, e);
        }
    }

    protected Class<?> resolveClass(
            String alias) {
        if (alias == null)
            return null;
        try {
            return resolveAlias(alias);
        } catch (Exception e) {
            throw new BuilderException(
                    "Error resolving class. Cause: "
                            + e, e);
        }
    }

    protected TypeHandler<?> resolveTypeHandler(
            Class<?> javaType,
            String typeHandlerAlias) {
        if (typeHandlerAlias == null)
            return null;
        Class<?> type = resolveClass(typeHandlerAlias);
        if (type != null
                && !TypeHandler.class
                .isAssignableFrom(type)) {
            throw new BuilderException(
                    "Type "
                            + type.getName()
                            + " is not a valid TypeHandler because it does not implement TypeHandler interface");
        }
        @SuppressWarnings("unchecked")
        // already verified it is a TypeHandler
                Class<? extends TypeHandler<?>> typeHandlerType = (Class<? extends TypeHandler<?>>) type;
        return resolveTypeHandler(
                javaType,
                typeHandlerType);
    }

    protected TypeHandler<?> resolveTypeHandler(
            Class<?> javaType,
            Class<? extends TypeHandler<?>> typeHandlerType) {
        if (typeHandlerType == null)
            return null;
        // javaType ignored for injected handlers see issue #746 for full detail
        TypeHandler<?> handler = typeHandlerRegistry
                .getMappingTypeHandler(typeHandlerType);
        if (handler == null) {
            // not in registry, create a new one
            handler = typeHandlerRegistry
                    .getInstance(
                            javaType,
                            typeHandlerType);
        }
        return handler;
    }

    protected Class<?> resolveAlias(
            String alias) {
        return typeAliasRegistry
                .resolveAlias(alias);
    }
}
